Bipolar disorder, also known as manic-depressive disorder, is highly influenced by the body's internal clock, or circadian rhythm. Maintaining a consistent sleep schedule can balance the circadian system, which can decrease the risk of episodes of mania or depression.
A study of 175 patients with bipolar disorder compared the effects of interpersonal and social rhythm therapy, which focuses on the regularity of sleep patterns and daily routines, and a program focusing on mood symptoms and management of medication side effects.
The patients who participated in interpersonal and social rhythm therapy were able to go longer without a new episode of mania or depression.
In a related study, researchers found that the genes that regulate circadian rhythms in mice also control the brain activity of dopamine, a neurotransmitter that affects motivation and emotion. Mice lacking certain circadian genes closely resemble bipolar patients in the manic state.